How Do Heat Pump Thermostats Work?

San Rafael

(415) 942-6565

Santa Rosa

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Heat Pump System

Air source heat pumps work by using electricity rather than natural gas, making them one of the most energy-efficient HVAC options for heating and cooling. Through this electric power, they use a compressor and condenser to take heat from outside air and transfer it into your home. This saves immensely on energy consumption by not having to exert a large amount of power conjuring up heat. It does the reverse of cooling the air, taking the warm air from inside and sending it outside. After reaching the desired temperature in the home, it will operate in cycles to maintain the comfortable temperature.

Emergency heat can begin running in heat pumps if temperatures are adjusted three or more degrees higher, using auxiliary heat to get to the desired temperature. But this operation of heating can quickly begin using a large amount of energy, which will raise your utility bills.

So how do you successfully operate your heat pump to be sure you are getting the most out of it while truly saving on energy? One of the best ways is to program the thermostat during the hot and cold seasons. There can be different thermostat technicalities for different heat pumps, but many operate similarly.

Heat Pump Thermostat Basics

Settings for thermostats will be the same for most electric heat pumps. The system switch is where you would change your thermostat setting to the desired mode, which will typically include the following:

Off: All parts of the system will shut off. If the fan switch is set, the indoor blower may still run.

Heat: When the thermostat calls for heat, the system will begin to transfer heat from the outside as warm or cold air to disperse inside. This is where the compressor and outdoor fan will start, with the reversing valve in the heat position to convert outdoor air into heat inside the home. Aux heat will turn on if greater heating is required to warm or heat the home. The outdoor coil can sometimes freeze if the outdoor temperature is severe enough, requiring a defrost mode to kick in. Aux heat will automatically turn on here to combat the cool air.

Cool: The air conditioning mode of the system will do the same thing as in the heat mode, but with the reversing valve in the cooling position, taking heat from the inside air and transferring the cool air into the home. Turning your heater into an AC system.

EM Heat: Used for extreme cold weather, if outside air gets below 32 or if there is an issue with the outdoor unit. This mode lets the thermostat set the auxiliary heat immediately by bypassing the compressor that moves the refrigerant and heat exchanger to extract heat from the outside. Aux heat will be the second stage of heating in most heat pumps, no matter the outside temperature.

Auto-TThermostat will automatically switch the heat pump between heat and cool mode if the indoor temperature goes above the cool temperature setpoint or below the heat temperature setpoint.

Most modern HVAC units will have a programmable thermostat that you can use to make sure your heat pump system is performing to the best of its ability and saving energy. It might be a round dial set up or a rectangle-shaped box that displays digital readings. If you are installing a programmable thermostat, it is important to make sure it is one that will be compatible with your specific heat pump system, since different heat pumps work in ways that could require a certain type of thermostat.

Adjust the settings accordingly to either warm or cool your house. It should take about an hour for the indoor temperature to reach what you put in the temperature setting. Since heat pumps are made to maintain temperatures by working gradually, it is best to set a comfortable temperature for your house and leave it at that. Making a large adjustment anywhere more than two degrees can lessen the heat pump’s efficiency since it will then kick into emergency heat mode. However, depending on the specific size and layout of your home, you may need to set the temperature of your heat pump a few degrees above the normal temperature setting to circulate more air and distribute it evenly throughout the home.

On the panel, you will also see both a “heat” mode and an “off” or “cool” mode. Leaving it on the auto setting will allow it to switch to heating or cooling even when you don’t want it to. Switch the thermostat setting as the seasons change in order to have the amount of hot or cool air you want in your living space.

For the fan switch, there are a different set of modes:

Auto: Where the fan will turn on at any time for both heating and cooling modes.

On: Where the fan will run continuously rather than in a cycle, typically for when you require more air circulation and filtration in the house.

Circ: Where the fan will run automatically as it does in the auto position, but this setting runs it on a cycle, regardless if there is a call for heating or cooling. Same benefits as the “on” position, but without the fan running constantly without stopping.


If you have a central heat pump, it is strongly recommended that you only use any backup heating system, such as a natural gas furnace, electric furnace, or fossil fuel furnace, as a last resort for extreme temperature demands. To make your heat pump the primary heating source, set your thermostat for the backup system 5 degrees below the heat pump thermostat. This will allow you to only use the backup system when a significant amount of heat is required.

How To Set Your Thermostat for Heat Pumps

There are different requirements for setting your heat pump’s thermostat based on whether you have a programmable or non-programmable thermostat. For non-programmable thermostats, you will have to make any adjustments manually, while programmable thermostats let you set up a schedule for different points of the day, saving you tons of money in energy bills by having the thermostat change automatically while you are sleeping or not in the house to manually reset it. There are thermostats that can create a different schedule for each day of the week, and there are ones that let you create a schedule for all weekdays and different ones for both Saturday and Sunday.

Non-Programmable Heat Pump Thermostat Settings

Heat: An average heat setting would be around 68 degrees. You can start here and gradually increase the temperature setting by one degree until it is at a setting you find comfortable. Making adjustments by more than one degree can cause the auxiliary heat to turn on even though you don’t need it to.

Cool: For cool mode, start by setting your thermostat at the average cooling temperature and gradually lower the setting by one degree until you find a comfortable cooling temperature.

Auto: Once you find your desired temperature settings for both heating and cooling, you can turn the system switch to auto mode, where the system will then automatically kick in the heating or cooling to reach your chosen set point temperature.

Programmable Heat Pump Thermostat Settings

Heat: On the scheduling screen, choose the day or group of days you want to schedule. Most heat pump heating systems will have four time periods on the thermostat: “wake,” “leave,” “return,” and “sleep.”. Set a comfortable temperature setting for the “wake” period (whatever time the first person gets out of bed), and then a setting 5–10 degrees lower than that for the “leave” period, which will be whenever the last person leaves the house for the day.

For the “return” period, set it back to the comfortable temperature setting for whatever time the first person returns home. Lastly, for the “sleep” period, enter a setting 3 or 5 degrees lower than your comfortable heating temperature at whatever time the last person goes to bed.

Cool: Follow the same steps as with heat, but for cooling. Set the temperature to 5 or 10 degrees warmer than the comfortable cooling setting for the “leave” period, and 2 or 4 degrees warmer than the comfortable setting for the “sleep” period.

You can always make temporary changes if you would like to adjust the thermostat for a day or a number of days by simply pressing the up or down buttons to change the temperature or by using the “hold” feature.

Auto: After you have your settings programmed, you can turn the system switch to auto mode and allow the system to turn on heating and cooling modes automatically to reach the target temperature.

How To Save Energy With Your Heat Pump

In order to be sure that you are getting the best operation abilities out of heat pump heating systems, there are a few things to keep in mind regarding the care of the unit. To get the most efficiency when trying to heat or cool your home, look to the advice below.

Heat Pump Preventative Maintenance

Keeping your heat pump unit clean and up-to-date is essential to making sure it continues to operate as it should. Make sure the outdoor unit has clean grates and coils. Be sure you are replacing your air filter regularly, since filters can become extremely dirty and block air circulation. Make sure you also see the manufacturer’s recommendations for maintenance. Having professional maintenance performed by specialists is always a good idea to make sure there are no serious problems with your unit that can grow into costly repairs and to make sure your unit remains energy efficient. Maintenance is especially important just before the summer or winter season, after a period of little use.

Ductless Mini Split Heat Pump

If you have a mini split unit, be sure to keep all the air vanes open and direct them downward for a heating cycle in the winter and upward for a cooling cycle in the summer. Also, set the temperature setting of the main heat pump unit slightly higher in order to evenly distribute heat throughout the house. Keep doors to rooms open if you are trying to heat or cool the entire house, or keep them closed if you are trying to target a specific area of the house. This will allow you to get the most out of your heat pump while conserving energy.

A heat pump is a heating and cooling solution revered for its operation efficiency. Using electric energy rather than fossil fuels can save you a ton on energy costs. Through winter and summer, your heat pump should work with the efficiency promised, working as an electric AC and electric heater and going through a cycle every couple of hours rather than staying on for long periods of time while struggling to provide adequate heating and air conditioning. But it is important to know which settings for the thermostat are the best to utilize when trying to heat or cool your home with a heat pump. Depending on your chosen temperatures and how you set your thermostat, you could be unnecessarily losing air. To make sure you are getting enough heat and cooling in your house, set your thermostat based on the above advice for the heating and cooling seasons.

Your Local Heat Pump Experts Are Here To Help

John Owens Services has been installing heat pump units into homes across Marin and Sonoma County for years. As a Mitsubishi Diamond Dealer, we are proud to say we are experts in the heat pump world. Whether you are looking at a ducted or ductless heat pump, we have you covered. Heat pump maintenance, repair, and replacement are just a phone call away. Gas prices are rising annually; now is the time to upgrade to a heat pump for your home.

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(415) 942-6565
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(707) 452-3464



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San Rafael
(415) 942-6565
Santa Rosa
(707) 452-3464